|Sir William de Montacute
Another name for William was John Montague.
From Reifsnyder-Gillam Ancestry, p. 51 :
Killed in a tournament (per Wikipedia)
William married Elizabeth FitzAlan d'Arundelle, daughter of Sir Richard FitzAlan 11th Earl of Arundel & 10th Earl of Surrey and Elizabeth de Bohun Countess of Arundel. (Elizabeth FitzAlan d'Arundelle was born on 8 Jul 1379 in Derbyshire, England and died on 8 Jul 1425 in Hoveringham, England.)
1 http://wc.rootsweb.ancestry.com/cgi-bin/igm.cgi, http://wc.rootsweb.com/cgi-bin/igm.cgi?op=DESC&db=nanatea&id=I33919.
2 Glenn, Thomas Allen, ed, Reifsnyder-Gillam Ancestry. (Philadelphia: (Privately Printed), 1902.), 51.
Wikipedia.org, William Montacute, 2nd Earl of Salisbury.